<template>
  <div>
    <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
      <div class="iconfont back-icon">&#xe624;</div>
    </router-link>
    <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
      <router-link to="/">
        <div class="iconfont back-icon">&#xe624;</div>
      </router-link>
      s我手机玩死我急死我
    </div>
  </div>
</template>

<script>
export default {
  name: 'detailheader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  activated () {
    window.addEventListener('scroll', this.handleScroll)
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = {
          opacity
        }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  deactivated () {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
  @import '~styles/veribles.styl'
  .header-abs
    position: absolute
    left: 0.2rem
    top: 0.2rem
    width: 0.8rem
    height: 0.8rem
    border-radius .4rem
    background rgba(0, 0, 0, 0.8)

  .back-icon
    color: #fff
    font-size 0.4rem
    text-align: center
    line-height: 0.8rem

  .header-fixed
    position fixed
    top: 0
    left: 0
    right: 0
    overflow hidden
    line-height: 0.86rem
    height: 0.86rem
    text-align: center
    font-size 0.32rem
    background: $bgColor
    color: #fff
    z-index 1000
    .back-icon
      color: #ffffff
      position: absolute
      left: 0
      top: 0
      text-align: center
      width: 0.64rem
      font-size 0.4rem
</style>
